VulnerabilityPublished 18 Oct 2026Updated 21 Oct 2026

CVE-2026-98733: Linux kernel · Bluetooth: hci_core: Serialize fragmented ISO packet queueing

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in d6d709981208567868c5c01ebd1bec5e5e7fdab0 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:30 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d6d709981208567868c5c01ebd1bec5e5e7fdab0, a7161730a3ab3f0a3896000db7ab0284683936e6, 708cdd203d0bbcf9255fffb2e4c308d5b28851a7 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 26afbd826ee326e63a334c37fd45e82e50a615ec, < d6d709981208567868c5c01ebd1bec5e5e7fdab0	Fixed in d6d709981208567868c5c01ebd1bec5e5e7fdab0
LinuxLinux	Affected ≥ 26afbd826ee326e63a334c37fd45e82e50a615ec, < a7161730a3ab3f0a3896000db7ab0284683936e6	Fixed in a7161730a3ab3f0a3896000db7ab0284683936e6
LinuxLinux	Affected ≥ 26afbd826ee326e63a334c37fd45e82e50a615ec, < 708cdd203d0bbcf9255fffb2e4c308d5b28851a7	Fixed in 708cdd203d0bbcf9255fffb2e4c308d5b28851a7
LinuxLinux	Affected ≥ 26afbd826ee326e63a334c37fd45e82e50a615ec, < 545fa70f730eb648a610a2f4b2d270865f77b619	Fixed in 545fa70f730eb648a610a2f4b2d270865f77b619
LinuxLinux	Affected ≥ 26afbd826ee326e63a334c37fd45e82e50a615ec, < 1a572db43c057566771b485598ad2e66cb390821	Fixed in 1a572db43c057566771b485598ad2e66cb390821
LinuxLinux	Affected =6.0	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Serialize fragmented ISO packet queueing The fragmented path in hci_queue_iso() calls __skb_queue_tail() without holding conn->data_q.lock. The socket lock serializes senders, but the transmit worker can concurrently remove packets from this queue using skb_dequeue(). After an insertion saves the old tail pointer, hci_sched_iso() can dequeue that packet and pass it to the driver. The driver can free the packet before the insertion resumes and writes to the old tail's next pointer, causing a use-after-free. Concurrent updates can also corrupt the queue. KASAN reported: BUG: KASAN: slab-use-after-free in hci_send_iso+0xc7d/0xe10 Call Trace: hci_send_iso+0xc7d/0xe10 iso_sock_sendmsg+0x710/0x900 __sys_sendto+0x34a/0x3a0 Allocated by task 86: __alloc_skb+0xdd/0x820 alloc_skb_with_frags+0x7e/0x770 sock_alloc_send_pskb+0x67a/0x820 bt_skb_sendmsg.constprop.0+0xc0/0x6c0 iso_sock_sendmsg+0x44e/0x900 Freed by task 90: kmem_cache_free+0xcb/0x3d0 vhci_read+0x33f/0x4d0 vfs_read+0x177/0xa20 Hold the queue lock across the entire fragment batch, as hci_queue_acl() does, to serialize insertion against dequeue while preserving fragment ordering.

References

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